The invention relates to a device for storing and releasing energy comprising a high pressure accumulator and a switch over device having two paths for the charging and discharging of the latter from and to a low pressure accumulator with the aid of a hydraulic transducer connected with means adapted to supply and to utilize energy with electrical control means and shut off valves to ensure that when the one said path is switched into an on condition the other path is switched into an off condition.
Known types of such energy storing and releasing devices have so far been so designed that, for bringing about the desired cooperation of the hydraulic transducer and the accumulators, relatively complex hydraulic switch over means are required between the accumulators and the ports of the hydraulic transducer. The accumulators themselves are each provided with a respective shut off valve. The valves required are relatively complex, and hence expensive, both as regards their individual structure and also as regards the system needed for operating them.